Dr Cameron Underwood
Research Fellow
Academic and research departments
Advanced Technology Institute, Nanoelectronics Centre, Department of Electrical and Electronic Engineering.My research project
Ab-initio calculations of the Structural and Electronic properties of Perovskite Solar Absorber Materials.
My research project focuses on ab-initio calculations, mostly using density functional theory (DFT). I study the structural and electronic properties of bulk 3D and 2D Ruddlesden-Popper perovskite solar absorber materials, with a particular focus on tin (Sn) based materials.
Supervisors
News
In the media
My teaching
Physics PhD Demonstrator:
Scientific Investigation Skills 18/19, 19/20
Mathematical and Computational Physics Programming 18/19, 19/20
Mathematical and Computational Physics Tutorials 18/19
Quantum Physics 18/19
Energy & Entropy 17/18
From Atoms to Lasers 17/18
Nuclear Astrophysics 17/18
My publications
Publications
Cameron C. L. Underwood, J. David Carey, and S. Ravi P. Silva (2021) Nonlinear Band Gap Dependence of Mixed Pb–Sn 2D Ruddlesden–Popper PEA2Pb1–xSnxI4 Perovskites
Two-dimensional (2D) Ruddlesden–Popper perovskites (RPPs) of the form PEA2Pb1–SnI4 can be used as the tunable active layer in photovoltaics, as the passivating layer for 3D perovskite photovoltaics or in light emitting diodes. Here, we show a nonlinear band gap behavior with Sn content in mixed phase 2D RPPs. Density functional theory calculations (with and without spin–orbit coupling) are employed to study the effects of the short-range ordering of Pb and Sn in PEA2Pb1–SnI4 compositions with = 0, 0.25, 0.5, 0.75, and 1. Analysis of the partial density of states shows that the energy mismatch of the Pb 6s and Sn 5s states in the valence band maximum determines the nonlinearity of the band gap, leading to a bowing parameter of 0.35–0.38 eV. This research provides a critical insight for the design of future metal alloy 2D perovskite materials. The positions of the tunable energy band discontinuity may point to intraband transitions of interest to device engineers.
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